I've been practicing my swing at home. Considering my normal field gun, which is a 5 lb single-shot, single-barrel 12 gauge, the 20" double gun doesn't swing all that differently. It doesn't really swing much at all. The extra barrel takes on the additional weight that a longer single barrel gun would have, but it does lose some centrifugal swing. That light single gun is certainly not the ideal trap gun, but it beats the pain of getting to station 5 and having trouble holding up and pointing a front-heavy gun. It's really easy to carry in the field too.
I use shorter and/or lighter barrels for very practical reason: Lupus, fibromyalgia, and two kinds of arthritis. These limitations have made me look to alternative tools in every area of life. As they say--"necessity is the mother of invention." It does take a lot of concentration to follow through with light guns, especially short ones, but my physical limitations make it impossible for me to shoot an entire game with a traditional gun, especially a double.
Also, I enjoy innovation. I like the "shoot what you brung" mentality. I don't have any dedicated "target guns" at all. Every gun I shoot is used in hunting as well as in target work. It's amazing how many ways you can take a squirrel -- .22 lr Ruger Single-Six, 9MM S&W combat pistol, .50 Cal. muzzleloader with saboted .454 round balls at 1000 ft/sec, any shotgun, .357 Mag revolver with .38 Spcl wadcutters, slingshot, etc. (Okay, I haven't taken any game with a slingshot, but I know a guy who claims he got a rabbit with one. I suppose it's possible.)
I appreciate your openness and encouragement. Sure, I'll miss a number of birds due to poor follow-through, but hopefully I'll get better with practice. It sure beats giving up shooting, which I'm NOT going to do.